This invention relates to the provision of a detachable gun barrel assembly for a weapon wherein the accuracy of the weapon is maintained during repeated cycles of detachment and reattachment.
The novel assembly includes an adapter for affixation to the receiver of the weapon to enable the detachable barrel of the invention to be used with existing weapons. More particularly, the present invention is directed to the combination of the adapter and a detachable gun barrel having at one end at least three regions of differing diameters. Square threads are located on an intermediate region of the barrel end for attachment to the adapter. The adapter is comprised of two parts: first, a mating end section which is provided with vee-threads to interengage with the receiver and, second, a receiving end section which is provided with internal square threads to interengage with the detachable barrel.
The ability to reduce the size of a weapon by detaching the barrel from the receiver is an important feature in weapon transport, storage and maintenance. In addition, the rifling in a weapon barrel is known to wear as a result of repeated use often requiring replacement. One approach to solving this problem is to use a segmented barrel as shown in U.S. Pat. No. 4,546,564 which discloses the use of a threaded releaseable connection between barrel segments. As shown therein, the sections are provided with vee-threads bounded by chamfered ends to provide a mechanical stop and a gas seal between the segments. The use of vee-threads and chamfered surfaces is likely to result in uneven wearing during repeated use. As a result, the accuracy of the weapon degrades as the worn surfaces of the angled parts of the attachment structure allow relative movement therebetween. A similar type of two-part barrel construction with vee-threads is shown in U.S. Pat. No. 4,660,312 wherein chamfered surfaces are used to positively register the barrel sections together. Again, uneven wearing of angled surfaces over a period of time can result in a reduction in accuracy of the weapon.
Different constructions for gun barrels have been used to protect against wear occurring over periods of prolonged use including the use of a gun barrel liner as shown in U.S. Pat. No. 3,442,172. The patent teaches the use of particular metals to provide a barrel liner which is secured to the barrel by a combination of square threads and swaging to form the rifling in the liner. The square threads in combination with an internal shoulder provided in the barrel are used for attachment. The patent teaches the importance of securing the liner to the barrel to form a unitary structure so as to prevent distortion and maintain a close fit.
Accordingly, the present invention is directed to the provision of a detachable gun barrel assembly which includes an adapter for coupling a square threaded replaceable barrel to a conventional receiver of the type having vee-threads. In addition, the invention includes multiple limiting stops which aid in obtaining and maintaining the registration of the elongated barrel with the adapter. Thus, the repeated separation of the barrel from the adapter is accomplished without the wearing of angled contact surfaces. The use of square threads and orthogonal surface stops essentially eliminates the effect of wear through repeated detachments from adversely affecting the accuracy of the weapon.